Mississippi Embayment Regional Aquifer Study (MERAS)

Fresh ground-water in the Mississippi embayment can be found in alternating formations of sand, silt and clay. Decades of pumping from the Mississippi River Valley alluvial aquifer for irrigation and from the Sparta-Memphis aquifer for industry and public-water supply have affected ground-water levels throughout the Mississippi embayment in Arkansas, Louisiana, Mississippi, and Tennessee. Ground-water withdrawals for agriculture have caused water-level declines in the alluvial aquifer in Arkansas of at least 40 feet in 40 years while withdrawals from the Sparta-Memphis aquifer have resulted in declines of more than 390 feet since the 1920's. These declines have prompted concerns over water availability and quality for both agriculture and industry.

Map showing Mississippi Embayment.

The purpose of the Mississippi Embayment Aquifer Study (MERAS) is to assess the ground-water availability (status and trends) of the Mississippi embayment aquifer system. The study area covers portions of eight states including Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. The MERAS study involves the refinement of model framework, input data compilation, model calibration, simulation of climate variability impacts, and ground-water availability estimation. The active model grid covers approximately 70,000 square miles, and incorporates some 6,000 miles of major rivers and over 100,000 water wells. Additional objectives of the study are to systematically estimate water budget components for the ground-water flow system and evaluate the existing water-level monitoring and recommend improvements in monitoring network design

For more information on the Mississippi Embayment Regional Aquifer Study (MERAS) project please visit the project's web page at the following URL: http://ar.water.usgs.gov/meras/index2.php

Publications
	Scientific Investigations Report 2008-5149 Summary of Aquifer Test Data for Arkansas--1940-2006, by Aaron L. Pugh
	Scientific Investigations Report 2008-5138 Evaluation of Selected Model Constraints and Variables on Simulated Sustainable Yield from the Mississippi River Valley Alluvial Aquifer System in Arkansas, By John B. Czarnecki
	Water-Resources Investigations Report 2003-4233 Conjunctive-use Optimization Model of the Mississippi River Valley Alluvial Aquifer of Southeastern Arkansas, by John B. Czarnecki, Brian R. Clark, and Greg P. Stanton
	Water-Resources Investigations Report 2003-4232 Recalibration of a Ground-water Flow Model of the Mississippi River Valley Alluvial Aquifer in Southeastern Arkansas, 1918, with Simulations of Hydraulic Heads Caused by Projected Ground-Water Withdrawals, by Greg P. Stanton and Brian R. Clark
	Water-Resources Investigations Report 2003-4231 Conjunctive-Use Optimization Model and Sustainable-Yield Estimation for the Sparta Aquifer of Southeastern Arkansas and North-Central Louisiana, by Paul W. McKee, Brian R. Clark, and John B. Czarnecki
	Water-Resources Investigations Report 2003-4230 Conjunctive-Use Optimization Model of the Mississippi River Valley Alluvial Aquifer of Northeastern Arkansas, by John B. Czarnecki, Brian R. Clark, and Thomas B. Reed
	Water-Resources Investigations Report 2003-4132 Development and Calibration of a Ground-Water Flow Model for the Sparta Aquifer of Southeastern Arkansas and North-Central Louisiana and Simulated Response to Withdrawals, 1998-2027, by Paul W. McKee, Brian R. Clark, and John B. Czarnecki
	Water-Resources Investigations Report 2003-4109 Recalibration of a Ground-Water Flow Model of the Mississippi River Valley Alluvial Aquifer of Northeastern Arkansas, 1918-1998, with Simulations of Water Levels Caused by Projected Ground-Water Withdrawals, by Tom B. Reed